Could be a simple one, often is. Some cheeky sod has probably removed the 4WS fuse so that the light doesn't come on, not cool, not to mention misleading and dangerous actually.
Get the fuse in and see what's what, pull any codes if the light comes on and post them up.
Most of the time it's something simple like a wheel sensor / spilt gaiter chucking grease over it, or if it's the 4WS itself, at worst it's often a dry solder in the ECU, which is a simple fix.
